Multiple tube heat exchanger forced air flow warm air furnace



i 6, 1954 F. T. ETHEREDGE MULTIPLE TUBE HEAT EXCHANGER FORCED AIR FLOW WARM AIR FURNACE 4 Shegts-Sheet 1:

Filed Nov. 17, 1950 3 INVENTOR. Franajs f'fi'zfhered e/ ATTEI RN EYS Apnl 6, 1954 F. T. ETHEREDGE 2,674,240

MULTIPLE TUBE HEAT EXCHANGER FORCED AIR FLOW WARM AIR FURNACE Filed Nov. 17, 1950 4 Sheets-Sheet 2 ATTEI RN EYS April 1954 F. T. ETHEREDGE D E C R 0 FE C RA wN Nm AF H CR XI EA W E HW EW BO UL TF mm PA I m U M 4 Sheets-Sheet 3 Filed Nov. 17, 1950 ATTCI RN EYE Aprll 1954 F. T. ETHEREDGE 2,674,240

MULTIPLE TUBE HEAT EXCHANGER FORCED AIR FLOW WARM AIR FURNACE Filed Nov. 17, 1950 4 Sheets-Sheet 4 u 1 i 9) 5 l2 2 I,

v INVENTOR. I francjsffizherecge,

ATTDRNEYS Patented Apr. 6, 1954 UNITED STATES MULTIPLE TUBE HEAT EXCHANGER FORCED AIR FLOW WARM AIR FUR- NACE PATENT OFFICE 1 Claim. 1

This invention relates to a heating system, and more particularly to a warm air furnace for domestic or other uses.

The object of the invention is to provide a warm air furnace which has an unusually high heating efficiency, the heating system of the present invention being constructed so that the air being heated is caused to travel over conduits or tubes which convey the hot products of combustion.

Another object of the invention is to provide a heating system which is constructed so that the elements or parts thereof are readily accessible for repair or cleaning, as when soot accumulates on these parts.

Still another object of the invention is to provide a warm air heating system in which the hot gases or products of combustion, as well as the air to be heated are caused to follow a tortuous path through the furnace, the furnace of the present invention being constructed so that the hot air to be heated passes to the top of the furnace and then is directed to the nearest point where the hot or burnt gases leave the furnace, the air then traveling in a direction opposite to the direction in which the hot gases are traveling, the air moving in a general direction downwardly, while the hot gases travel generally upwardly.

Still another object of the invention is to provide a heating system which has a maximum heating surface, the high efficiency of the present invention enabling a smaller burner or other heating medium to be used.

A further object of the invention is to provide a heating system which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

Figure 1 is a vertical sectional view taken through the furnace of the present invention;

Figure 2 is a sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a sectional view taken on the line 3-3 of Figure 1;

Figure 4 is a top plan view of the furnace constructed according to the present invention;

Figure 5 is a sectional view taken on the line 5-5 of Figure 1.

Referring in detail to the drawings, there is shown a furnace which comprises a horizontally disposedbase In that may be fabricated of any suitable material. Extending upwardly from the base and supported thereby is a hollow housing H. The housing H includes a top wall 8 and spaced parallel, vertically disposed side walls [2 and M, Figure 5. A pair of spaced, parallel end Walls or panels l5 and It, which may be insulated, extend between the side walls l2 and I l, and are detachably connected thereto. Thus, when the parts within the housing H are to be cleaned of soot, or repaired or replaced, the panels 15 and it can be readily removed.

Arranged in the bottom of the housing It is a compartment Ii, and positioned in the compartment i! is an air blower I8 which is adapted to be driven by the electric motor l9 and belt 20. A duct 2| permits air to be sucked through into the compartment ll, while a duct 22 serves to convey air from the compartment ll into the lower end of a passageway 23 that extends vertieally through the housing along the side wall 12, whereby the air that is to be heated is conveyed or transmitted initially to the top of the housing H. A filter element 2 5 is arranged at the entrance of the compartment I? so that no foreign matter will be sucked or forced through the furnace.

The blower compartment ii may be surrounded by suitable insulation 25, and a door 26 is detachably connected to the housing II by latches 2?, so that by removing the door 26 by means of the handle 9, a person can gain access to the compartment ll in order to replace or repair the blower l8.

Arranged adjacent the compartment ll in the bottom of the housing H is a burner 28 which may be of the oil-burning type. The hot gases or products of combustion from the burner 28 pass into a combustion chamber 29, Figure l, and the chamber 29 may be surrounded by suitable refractory material tii. An inclined partition 3! extends along the top of the chamber 29. Extending through the housing II is a plurality of horizontally disposed, parallel tubes 32. The tubes 32 are adapted to have pass therethrough the gases from the combustion chamber 29, the tubes 32 conveying the hot gases upwardly in the housing H, while the air to be heated travels downwardly in the housing H and along the outside of the tubes 32.

It will be seen from Figures 1 and 5 of the drawings that the tubes 32 are of less length than the housing I I so that hot gases from the chamber 29 pass first into one end of the lowermost bank of tubes 32 (Figure 1), and these hot gases pass to the right through the tubes 32 in the di-- i'ection indicated by the arrows, Figure 1. Suitable vertically disposed partitions 33 extend between each set or bank of tubes 32, and also arranged between each bank or set of tubes 32 is a horizontally disposed baflie plate 34. The partitions 33 and baffle plate 34 serve to guide the hot gases and air being heated during their movement through the housing.

The gaseous products of combustion, after passing through the tubes 32, leave the top of the housing I I through the fiue 35, Figures 1 and 4. These products of combustion can be discharged into the atmosphere as. waste: The air which is to be heated passes up through thepassageway 23, thence through a horizontally disposed chamber 36, Figure 3, and then this air is forced down through the spaces around the tubes 32. that air to be heated can pass from the chamber 36 down around the tubes 32.

After the air has reached the area in the vicinity of the lowermost tubes 32, the air passes through a horizontally disposed chamber 38 into the lower end of a passageway 39. The passageway 39 serves to convey the hot air upwardly in the housing H, so that the air goes through an opening 40 and into suitable registers for heating the desired rooms in a home or other building. Suitable insulation 4! may be arranged contiguous to theside wall [4, while other insulation 42 is arranged contiguous to the other side wall l2. Also, insulation 43 maybe arranged in surrounding relation with respect to the tubes 32.

In use, the burner 28 produces the hot gases or products of combustion which enter the open ends of the lowermost tubes 32 (left end of Figure 1), through the chamber 29. These hot gases pass longitudinally through the lowermost tubes 32 (from left to right in Figure 1), then the hot gases leave or pass out of the open ends of the tubes 32 and enter the open right ends of the next higher set of tubes 32. The hot gases pass through the second bank of tubes 32, passing from right to left, Figure 1, and these hot gases continue to pass from each set of tubes to the next set of tubes above, until finally, the gases pass out through the flue 35 in the top of the housing I I. Meanwhile, the blower i8 is forcing or circulating air up through the passageway 23 until it reaches the top of the housing II, and this air to be heated passes down through the space between the tubes 32, whereby the heated tubes 32 cause the air to be heated. The heated air finally enters the chamber 38 in the lower portion of the housing I I and then enters the passageway 39. The heated air passes up through the passageway 39 until it goes out through the opening 40 into registers or into the rooms to be heated. The baffle plates 34 and partitions 33 insure that the air and gases fol- ,low the proper paths.

From the foregoing, it is apparent that a furnace has been provided in which the hot gases The top bafiie plate'-3l"is arranged'so in which the burnt gases are traveling. The air moves in a general direction downwardly, while the heat or hot gases travel in a general direction upwardly. The air then leaves the hottest part of the furnace, passing up an insulated duct 39 at the side of the furnace, to the top, where it is then conveyed to the rooms which are to be heated. The arrangement of narrow tubes 32 provides for a far greater number 'of square inches of heating surface, and also these tubes are accessible from each end, so that they can be conveniently. cleaned or replaced. The high emciency. of thezsystem of the present invention enables a burnerof smaller capacity to be used. Although an oil burner has been indicated as the source 'ofheat, provision can also be made for the useof natural or manufactured gas instead of" oil. If desired, an automatic humidifier may be'used.

I claim:

In a furnace, a horizontally disposed'base; a hollow housing supported on said base, said housing including a pair of spaced parallel vertically disposed side walls, apair of spaced parallel vertically disposed detachably arranged end walls, a flue projecting from the top of said housing, means defining a compartment in the lower end of said housing, a blower positioned in saidcompartment, means defining a passageway extending along one of said side walls, the-lower end of said passageway communicating with said compartment and the outlet from the blower, the upper end of said passageway communicating with th space within the housing, a burner positioned in the bottom of said housing, means defining a combustion chamber in said housing for receiving hot gases from said burner, a plurality of parallel spaced open ended tubes extending across the interior of said housing with their ends disposed opposite to and in spaced relation with said detachably arranged end walls, means in said housing cooperating with said detachably arranged end walls to define passageways connecting said tubes in a pluralityv of continuous series, one end of each of said series communicating with th combustion chamber, and the other end of said series communicating with the flue for conveying the hot gases from said combustion chamber upwardly through said housing to said fiue, the air from the upper end of said passageway passing'downwardly in said housing between said tubes, means defining. a second passageway extendingupwardly through said housing for conveying the heated air'from the bottom of the housing out through'thetop thereof, said second passageway havingitslower end communicating with the space within the housing and its upper end communicating with an outlet from the housing for heated air, there being an inlet to the housing for air tobe heated, said inlet communicatingwith the. compartment and with an inlet to the blower.

References Cited in the file Of' this patent" UNITED STATES PA'IIEINTS Number Name Date 311,502 Mann Feb. 3, 1885 1,126,873 Sample Feb. 2, 19 15 1,935,852 Long Nov. 21, 1933 2,192,636 Briggs Mar; 5, 19.40 2,240,161 Mueller Apr. 29, 1941 2,241,303 Grebe May'6,-.1941 2,363,742 Norton- .Nov. 28, 1944 2,532,089 Crell Nov. 28,1950 

